The present invention relates to a valve which has a closure member having a regular curved exterior surface, such as a ball, conical or cylindrical plug-like member, butterfly valve disc, or ball calotte, which operates to attenuate the flow of fluids or medium passing through the valve.
In the field of flow passages and the utilization of pipes to direct flow, valves have been utilized to distribute the pressure drop into several phases and to control and stop flow. In the prior art it is known that a closure member may be furnished with a punched plate-like attenuator device, which has been disposed in a transverse position with regard to the longitudinal direction of the flow passage past the closure member. Such prior art attenuator devices are disadvantageous when the valve is fully open, because when the valve is fully open the attenuator device operates to restrict the flow capacity. On the other hand, if there is no attenuation or little attenuation, cavitation is produced in the valve, causing vibration, noise and wear, at high pressure ranges, especially where compressible fluids are employed.